Genetics

2 12/11/12 WHAT IS GENETICS? From Wikipedia: GeneticsGenetics - the science of genes, heredity, and the variation of organisms

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7 12/11/12 FOR THOUSANDS OF YEARS, PEOPLE WERE DOING GENETICS WITHOUT EVEN KNOWING IT, THEY SELECTED THE TRAITS IN PLANTS AND ANIMALS THAT THEY WANTED AND BRED FOR ONLY THOSE TRAITS. 7

Gregor Mendel ?

12/11/12 Introducing the Punnet Square!

11 12/11/12 TERMS TO REMEMBER: GENOTYPES: exactly what gene alleles are carried PHENOTYPES: what shows on the surface DOMINANT (TT) / RECESSIVE (tt) HOMOZYGOUS/HETEROZYGOUS (TT/Tt)

12 12/11/12 GREGOR MENDEL, A EUROPEAN MONK IN THE 1800S, RESEARCHED PEA PLANTS HE CAME UP WITH THIS: 1.The inheritance of each trait is determined by "units" or "factors” passed on to descendents unchanged (Alleles on our genes) 2. For each trait, an individual inherits one such unit OR ALLELE from each parent 3. That a trait may not show up in an individual but can still be passed on to the next generation.

13 12/11/12 Genetic Research isn’t new Genetic modification to corn has been going on for almost 9000 years. Even “modern” hybrid corn development started in 1908 with the discovery of Hybrid Vigor

14 12/11/12 Hybrid Vigor Cross two corn plants with favorable characteristics The “hybrid” seed produced from the mating would be superior to both parents when planted and grown.

15 12/11/12 Corn Hybrids: the Superheroes of corn? WHO is the parent?

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17 12/11/12 LET’S TALK RATIOS AND PERCENTAGES

18 12/11/12 ALBINO: GREEN CORN RATIOS AND PERCENTS GREEN PLANTS: ______ (YOURS) ________ (CLASS) WHITE PLANTS: ______ (YOURS) ________ (CLASS) TOTAL PLANTS: ______ (YOURS) _______ (CLASS) RATIO GREEN/WHITE: ______ (YOURS) _____ (CLASS)

19 12/11/12 GREGOR MENDEL: “EXPECTED RATIOS” FOR THE F1 AND F2 GENERATIONS: F1 = ALL DOMINANT: 100% F2 = 3 DOMINANT: 1 RECESSIVE 75% : 25%

20 12/11/12 BUT, JUST BECAUSE WE EXPECT SOMETHING, DO WE ALWAYS GET IT ???

21 12/11/12 YELLOW KERNELS: ______ (YOURS) ________ (CLASS) PURPLE KERNELS: ______ (YOURS) ________ (CLASS) TOTAL KERNELS: ______ (YOURS) ________ (CLASS) RATIO YELLOW TO PURPLE: ________ (YOURS) ______ (CLASS) YELLOW VS. PURPLE CORN KERNELS RATIOS AND PERCENTS

22 12/11/12 THE BIGGER THE SAMPLE SIZE, THE MORE THAT “ACTUAL” = “EXPECTED”

23 12/11/12 ARE WE MISSING SOMETHING? LET’S TAKE A STEP BACK

24 12/11/12 Regular body cells (2 alleles/trait) reproduce in a process called: MITOSIS

25 12/11/12 Aa SO A REGULAR CELL Reproduces through Mitosis and ends up With two cells the same As the parent THESE ARE CALLED: DIPLOID CELLS BECAUSE THEY HAVE 2 ALLELES FOR A TRAIT

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27 12/11/12 BUT WAIT A MINUTE… IF EACH PARENT CELL HAS 2 ALLELES FOR A TRAIT AND THE TWO PARENT CELLS COMBINE, WOULDN’T YOU HAVE A SEED WITH 4 ALLELES?

28 12/11/12 PLANT SEEDS: - POLLEN FROM THE “DAD” - AN EGG FROM THE “MOM” -A SEED WITH ALLELES FROM BOTH PARENTS

29 12/11/12 BUT POLLEN AND EGGS ARE NOT REGULAR CELLS. THEY HAVE HALF THE CHROMOSOMES. THAT MEANS HALF THE ALLELES THEY ARE HAPLOID CELLS HOW CAN THIS HAPPEN? (Hint: Remember we mentioned Meiosis earlier???)

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31 12/11/12 SO IN MEIOSIS: A DIPLOID CELL (WITH 2 ALLELES), DOUBLES TO 4 ALLELES THEN SPLITS INTO 4 HAPLOID CELLS (1 allele each)

32 12/11/12 AT FERTILIZATION, ONE ALLELE FROM EACH PARENT COMBINES TO FORM: THE EMBRYO THAT BECOMES THE CHILD…. WITH TWO CHROMOSOMES

33 12/11/12 Dr. Peter Balint-Kurti The genetic basis for quantitative disease resistance in maize. also known as partial disease resistance, – Usually it is enough to protect the plants Grant from the National Science Foundation

34 12/11/12 WRITE DOWN YOUR RESULTS AND SET THEM ASIDE…... HEADS ( YOUR GROUP) ________ TAILS (YOUR GROUP) ________ TOTAL FLIPS (YOURS) ________

35 12/11/12 WITH ALL THAT MIXING AND SPREADING OF ALLELES, HOW DO WE PREDICT WHO ENDS UP WITH WHAT TRAIT???

36 12/11/12 Dr. Balint-Kurti’s research: The genetic basis for:quantitative disease resistance in maize. :quantitative disease resistanc It also known as partial disease resistance, Usually it is enough to protect the plants